1. Field of the Invention
This invention relates generally to the field of large electrodynamic systems, such as electrical power generators. More specifically, this invention relates to an improved system and method for protecting an end winding region of such a system from vibrational or other fatigue damage.
2. Description of the Prior Art
Large electrical power generators of the type that are designed and manufactured by the assignee of this invention, Westinghouse Electric Corporation, produce, in addition to electricity, heat and vibration. Generator components, such as coil portions in the stator end winding regions, must be designed to withstand as many cycles of the stresses and relative motion that are attendant to such heat and vibration as possible.
In the past, the aggregated stator coil end windings of certain large electrical generators were unitized with the stator core by bolting and wrapping. In such designs, however, vibrations from the stator core were transmitted directly to the end winding regions, causing wear. In an effort to mitigate this problem, many present generators incorporate a decoupled design in which the stator coil end winding regions are isolated from the stator core, with the only connection to the core being from the coils themselves. In the decoupled design, a number of bands are used to bind the top and bottom coils together to prevent relative movement. In manufacturing the end winding arrangement, each band must be individually pretensioned to a desired extent. This process, although effective, is quite expensive, both in terms of components and the amount of labor that is required.
It is clear that a long and unfilled need has existed in the prior art for an improved method and system for securing a stator end winding region in an electrodynamic system against heat-induced and vibratory stresses that will occur during system operation.